“They lived like the young people of their age, dressed like them,” said their father, who was called in by Moroccan police early on Saturday.

“Moussa was a nice boy who didn’t hurt anyone.

“He was attending classes and was going to take his high school exams next year. He recently started praying… but it stopped there.”

He said the young man, who has three sisters, had “doubtless” been manipulated.

A cousin said Moussa “loved playing football, having a good time, chatting up girls”.

He travelled to Morocco almost every year for the summer holidays and was expected back last Tuesday, the cousin said.

“The last few months, he started to become interested in religion. He used to go to a mosque in Ripoll. Maybe that’s where he was brainwashed,” he said, adding that the brothers’ parents had recently divorced.

Their father said that Driss, the older brother, had “left school early to work honestly and earn a living”.

“Today he is between the hands of God and the police. He is under investigation. I hope they will say he’s innocent. I don’t want to lose both my sons.”